AC Input Circuit Asynchronous Load Switching for Signal Accuracy

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing input circuits for alternating current signals face issues with capacitive coupling, leading to false signal readings due to long distance runs and high voltage proximity, which can result in invalid logic signals and overheating of electronic load banks.

Innovation Solution

An input circuit that outputs a control signal to switch a load asynchronously with respect to the alternating current signal for a predetermined time, determines the activity of the logic signal, and sets states accordingly, with delayed repetitions to prevent overheating and false signal interpretation, using a processor and electronic load bank to selectively turn on and off the load bank based on valid switch closures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the conductors travel a long distance in close proximity to carry the input signal, then the signal can be transmitted over long distances, but capacitive coupling occurs between the conductors and nearby power lines, causing false signal readings

Engineering Contradiction:
Improvecable lengthVSAvoidsignal accuracy
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent applies periodic action by turning on the electronic load bank in periodic intervals to periodically discharge the capacitive coupling between conductors and power lines. This periodic discharge prevents false signal readings by eliminating the accumulated capacitive voltage that would otherwise be misinterpreted as valid logic signals during long cable runs.

Inventive Principle:
Principle #19Periodic action

2Reliability

If the electronic load bank is turned on continuously to discharge capacitive coupling, then false signal readings are prevented, but the load bank overheats

Engineering Contradiction:
Improvesignal accuracyVSAvoidload bank temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent uses periodic action by cycling the electronic load bank on and off in controlled intervals. The load bank is activated periodically to discharge capacitive coupling, then turned off to cool down, preventing overheating while maintaining signal accuracy. This periodic operation allows the load bank to perform its function without continuous thermal stress.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies dynamics by making the load bank operation dynamic rather than static. The system continuously monitors for false signals and dynamically adjusts the load bank state, turning it on only when capacitive discharge is needed and turning it off when cooling is required. This dynamic control optimizes both signal reliability and thermal management.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If the input impedance is increased to reduce current draw, then power consumption is reduced, but the cable capacitance must be kept very low, limiting cable length

Engineering Contradiction:
Improvepower consumptionVSAvoidcable length
Core Design Contradiction:
Use of energy by moving objectVSLength of stationary object

Solution Approach 1:

The patent introduces an intermediary mechanism - the electronic load bank - that actively manages the capacitive coupling effect. Rather than relying solely on high input impedance to minimize current draw, the system uses the load bank as an intermediary to periodically discharge the capacitance, enabling long cable runs with high-impedance inputs without suffering from false signals due to capacitive coupling.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution effectively reduces capacitive coupling issues, allowing longer cable runs without false signal interpretations and preventing overheating of the load bank by asynchronously operating the electronic load bank with appropriate delay times, ensuring accurate signal detection and maintaining the load bank's cool operation.

Implementation Method 1

The filter includes a first resistor connectable to sense a presence of a possible false control signal, and a second resistor, having much lower resistance than the first resistor, connected in a path between the control line input and circuit common

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2403125B1Input circuit for alternating current signal, and motor starter including the same
Publication Date: 2019.12.25 EATON INTELLIGENT POWER LTD
  • EP2403125B1 patent drawingFigure 1~4
  • EP2403125B1 patent drawingFigure 2
  • EP2403125B1 patent drawingFigure 3

AI summary

An input circuit (20) includes an interface (26) structured to output a logic signal (28) from an alternating current signal (22) of a pair of elongated conductors (24). A load (30) is switchable to the elongated conductors. A processor (32) outputs (35) a control signal (34) to switch the load to the elongated conductors asynchronously with respect to the alternating current signal for a first predetermined time, inputs (36) the logic signal, determines (158,160,162,164) if the input logic signal is active a plurality of times during the first predetermined time and responsively sets a first state of the alternating current signal, and, otherwise, sets an opposite second state of the alternating current signal, and delays (178) for a second predetermined time, which is longer than the first predetermined time, for the opposite second state before repeating the output, and, otherwise, delays (172) for a third predetermined time, which is longer than the second predetermined time, for the first state before repeating the output.